Landscapes are a broad subject (pun intended), generally suited to wider angle lenses, though it all depends what effect you are after. I've taken shots with an 18mm lens and wished I had wider, I've taken landscapes with 200mm lenses and been pleased with the results.
I'd say the secret of good landscapes is more to do with the elements of composition rather than the equipment. Take a look at this thread for example:
http://www.worldphotographyforum.com...read.php?t=288
I found the discussion on what makes the shot work very useful. I knew I liked crop 2 better, but it took Stephen's comments to make me understand
why.
Take a look around the landscapes gallery, there's plenty to chose from, it's one of our most popular categories. Look at a selection of pictures that you like and try and understand why you like them. The difficulty in landscapes is trying to capture a sense of scale. One of the best pictures I've seen that achieves this is:
http://www.worldphotographyforum.com...hoto=722&cat=2
It all really boils down to personal taste, but IMHO, landscapes are more to do with composition than equipment. Having said that, a tripod is essential, but you've got one of those I see, you may also want a wider lens than 28mm depending on the style of landscape you are aiming for.
Regards,
Duncan.